Sub-bandgap laser-induced fluorescence in the CaF2 via a linear process

IF 3.3 3区物理与天体物理 Q2 OPTICS

Journal of Luminescence Pub Date : 2024-12-09 DOI:10.1016/j.jlumin.2024.121023

Mariem Guesmi , Tomáš Thoř , František Procháska , Martina Hlubučková , Vít Kanclíř , Oumayma Taboubi , Ivana Šeděnková , Karel Žídek

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引用次数: 0

Abstract

Calcium fluoride (CaF₂) is an excellent material for deep-ultraviolet optics. However, exposure to intense UV laser light can induce new defects in the material, a phenomenon known as laser-induced fluorescence (LIF). In our study, a femtosecond laser with a wavelength of 257 nm (4.82 eV, i.e., below CaF₂ bandgap) was used to induce the LIF. We thoroughly studied the phenomenon behind the photoluminescence (PL) and its variation. Based on its linear excitation intensity dependence, we assigned the PL below 3.4 eV to sub-bandgap defect emission. The rate of LIF in this spectral region also scaled linearly with the irradiation pulse intensity. At the same time, the LIF rate was strongly dependent on the repetition rate. Our results suggest that laser-induced heating is responsible for the observed PL changes. We rationalized our observations based on the formation of F- and M-centres in CaF₂.

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来源期刊

Journal of Luminescence 物理-光学

CiteScore

6.70

自引率

13.90%

发文量

850

审稿时长

3.8 months

期刊介绍： The purpose of the Journal of Luminescence is to provide a means of communication between scientists in different disciplines who share a common interest in the electronic excited states of molecular, ionic and covalent systems, whether crystalline, amorphous, or liquid. We invite original papers and reviews on such subjects as: exciton and polariton dynamics, dynamics of localized excited states, energy and charge transport in ordered and disordered systems, radiative and non-radiative recombination, relaxation processes, vibronic interactions in electronic excited states, photochemistry in condensed systems, excited state resonance, double resonance, spin dynamics, selective excitation spectroscopy, hole burning, coherent processes in excited states, (e.g. coherent optical transients, photon echoes, transient gratings), multiphoton processes, optical bistability, photochromism, and new techniques for the study of excited states. This list is not intended to be exhaustive. Papers in the traditional areas of optical spectroscopy (absorption, MCD, luminescence, Raman scattering) are welcome. Papers on applications (phosphors, scintillators, electro- and cathodo-luminescence, radiography, bioimaging, solar energy, energy conversion, etc.) are also welcome if they present results of scientific, rather than only technological interest. However, papers containing purely theoretical results, not related to phenomena in the excited states, as well as papers using luminescence spectroscopy to perform routine analytical chemistry or biochemistry procedures, are outside the scope of the journal. Some exceptions will be possible at the discretion of the editors.